For an electronic apparatus of splittable type required to create the stereosonic effect, the users wish that two or more speaker portions can be jointed and separated quickly and simply so as to carry the electronic apparatus of splittable type easily. Meanwhile, the number of the jointing members between two speaker portions should be as less as possible, and the integrity and the beauty of the appearances of the speaker portions should not be influenced after being jointed and separated frequently. In order to achieve the miniaturization of the electronic apparatus of splittable type, the efficacy per unit volume of each speaker portion should be as high as possible, which is a target having been sought by the manufacturers all along. Up to now, however, in the electronic apparatus of splittable type comprising two or more speaker portions, the speaker portions having no joint-separate relationship in general, which are separated from one another and stored alone, typically should be electro-connected by the external wires when being used. Alternatively, even though these speaker portions have the joint-separate relationship, they are jointed substantially by way of rotary engagement, buckling, buttons or bolts, these conventional jointing mechanisms being troublesome and time-consuming in operation and the surfaces of the jointed portions being liable to be scratched and worn, resulting in the beauty and lifespan of products being affected.
For example, with a sound case, many users wish to enjoy the stereosonic effect in outdoor entertainments, so that they should often carry two or more miniature sound cases, which are separated by a proper space when being used and connected using wires to the audio electronic signal outputting devices such as PMP (Portable Media Player), PDA (Personal Digital Assistant) or portable computer. After entertainments, the wires must be removed and rewound respectively, the sound cases must be handled carefully, these sequential operations spend a lot of time and effort and deteriorate the enjoying quality very much even eliminate the “true portable music enjoyment”, in addition, these frequent operations would scratch the outer surfaces of the sound cases and shorten the lifespan thereof. Therefore, it is the urgent requirement of the users that the product designers should develop a portable sound case which has a small and exquisite figure so as to be carried easily but excellent tone quality, and can be jointed and separated simply and quickly. Of course, in order to achieve the miniaturization, it is necessary to contain the components in the sound case as much as possible on the premise that the tone quality of the sound case does not be lowed. The voice chamber is an inner case which is provided directly with a speaker and resonated with the speaker. On the other hand, because the conventional structure of voice chamber, for example, a voice chamber with a rectangular shape in section, is difficult to form a sound case in compact structure to meet the requirement of miniaturization in the particular environment, the structure of the voice chamber of the prior art must be improved in order to make use of the containing space of the sound case sufficiently.